2/28/2012 5:08 PM PST BY TMZ STAFF

Krista Allen is KO-ing her marriage to the guy who KO'd Jesse Metcalfe in the most epic Hollywood fight video ever ... TMZ has learned.

Allen -- who starred as the hot lesbian in "Anger Management" and the busty elevator girl in "Liar Liar" -- has filed for divorce from Mams Taylor ... a British rapper who dabbles in MMA.

According to the divorce docs filed in L.A. County Superior Court, the two married in October 2010 ... but separated in August 2011 ... less than a year after they tied the knot.

In the docs, Krista blames the split on irreconcilable differences. They have no children together.

Fun fact -- Krista famously dated George Clooney around 2002.

As for Mams ... dude made his mark on the Thirty Mile Zone back in 2008 ... when he CLOCKED "Desperate Housewives" star Jesse Metcalfe with a ferocious haymaker ... after the two got into an argument outside of a private party at Boulevard 3 nightclub.